include/uapi/linux/target_core_user.h

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef __TARGET_CORE_USER_H
   3 #define __TARGET_CORE_USER_H
   4
   5 /* This header will be used by application too */
   6
   7 #include <linux/types.h>
   8 #include <linux/uio.h>
   9
  10 #define TCMU_VERSION "2.0"
  11
  12 /*
  13  * Ring Design
  14  * -----------
  15  *
  16  * The mmaped area is divided into three parts:
  17  * 1) The mailbox (struct tcmu_mailbox, below)
  18  * 2) The command ring
  19  * 3) Everything beyond the command ring (data)
  20  *
  21  * The mailbox tells userspace the offset of the command ring from the
  22  * start of the shared memory region, and how big the command ring is.
  23  *
  24  * The kernel passes SCSI commands to userspace by putting a struct
  25  * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
  26  * userspace via uio's interrupt mechanism.
  27  *
  28  * tcmu_cmd_entry contains a header. If the header type is PAD,
  29  * userspace should skip hdr->length bytes (mod cmdr_size) to find the
  30  * next cmd_entry.
  31  *
  32  * Otherwise, the entry will contain offsets into the mmaped area that
  33  * contain the cdb and data buffers -- the latter accessible via the
  34  * iov array. iov addresses are also offsets into the shared area.
  35  *
  36  * When userspace is completed handling the command, set
  37  * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
  38  * and also set mailbox->cmd_tail equal to the old cmd_tail plus
  39  * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
  40  * should process the next packet the same way, and so on.
  41  */
  42
  43 #define TCMU_MAILBOX_VERSION 2
  44 #define ALIGN_SIZE 64 /* Should be enough for most CPUs */
  45 #define TCMU_MAILBOX_FLAG_CAP_OOOC (1 << 0) /* Out-of-order completions */
  46
  47 struct tcmu_mailbox {
  48         __u16 version;
  49         __u16 flags;
  50         __u32 cmdr_off;
  51         __u32 cmdr_size;
  52
  53         __u32 cmd_head;
  54
  55         /* Updated by user. On its own cacheline */
  56         __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
  57
  58 } __packed;
  59
  60 enum tcmu_opcode {
  61         TCMU_OP_PAD = 0,
  62         TCMU_OP_CMD,
  63 };
  64
  65 /*
  66  * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
  67  */
  68 struct tcmu_cmd_entry_hdr {
  69         __u32 len_op;
  70         __u16 cmd_id;
  71         __u8 kflags;
  72 #define TCMU_UFLAG_UNKNOWN_OP 0x1
  73         __u8 uflags;
  74
  75 } __packed;
  76
  77 #define TCMU_OP_MASK 0x7
  78
  79 static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
  80 {
  81         return len_op & TCMU_OP_MASK;
  82 }
  83
  84 static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
  85 {
  86         *len_op &= ~TCMU_OP_MASK;
  87         *len_op |= (op & TCMU_OP_MASK);
  88 }
  89
  90 static inline __u32 tcmu_hdr_get_len(__u32 len_op)
  91 {
  92         return len_op & ~TCMU_OP_MASK;
  93 }
  94
  95 static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
  96 {
  97         *len_op &= TCMU_OP_MASK;
  98         *len_op |= len;
  99 }
 100
 101 /* Currently the same as SCSI_SENSE_BUFFERSIZE */
 102 #define TCMU_SENSE_BUFFERSIZE 96
 103
 104 struct tcmu_cmd_entry {
 105         struct tcmu_cmd_entry_hdr hdr;
 106
 107         union {
 108                 struct {
 109                         __u32 iov_cnt;
 110                         __u32 iov_bidi_cnt;
 111                         __u32 iov_dif_cnt;
 112                         __u64 cdb_off;
 113                         __u64 __pad1;
 114                         __u64 __pad2;
 115                         struct iovec iov[0];
 116                 } req;
 117                 struct {
 118                         __u8 scsi_status;
 119                         __u8 __pad1;
 120                         __u16 __pad2;
 121                         __u32 __pad3;
 122                         char sense_buffer[TCMU_SENSE_BUFFERSIZE];
 123                 } rsp;
 124         };
 125
 126 } __packed;
 127
 128 #define TCMU_OP_ALIGN_SIZE sizeof(__u64)
 129
 130 enum tcmu_genl_cmd {
 131         TCMU_CMD_UNSPEC,
 132         TCMU_CMD_ADDED_DEVICE,
 133         TCMU_CMD_REMOVED_DEVICE,
 134         TCMU_CMD_RECONFIG_DEVICE,
 135         TCMU_CMD_ADDED_DEVICE_DONE,
 136         TCMU_CMD_REMOVED_DEVICE_DONE,
 137         TCMU_CMD_RECONFIG_DEVICE_DONE,
 138         TCMU_CMD_SET_FEATURES,
 139         __TCMU_CMD_MAX,
 140 };
 141 #define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
 142
 143 enum tcmu_genl_attr {
 144         TCMU_ATTR_UNSPEC,
 145         TCMU_ATTR_DEVICE,
 146         TCMU_ATTR_MINOR,
 147         TCMU_ATTR_PAD,
 148         TCMU_ATTR_DEV_CFG,
 149         TCMU_ATTR_DEV_SIZE,
 150         TCMU_ATTR_WRITECACHE,
 151         TCMU_ATTR_CMD_STATUS,
 152         TCMU_ATTR_DEVICE_ID,
 153         TCMU_ATTR_SUPP_KERN_CMD_REPLY,
 154         __TCMU_ATTR_MAX,
 155 };
 156 #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
 157
 158 #endif